Election Day 2015: Polls open in closest fought election battle in decades

Dawn breaks over the Houses of Parliament on the morning of the election

Britain goes to the ballot box today in the most uncertain General Election for decades, with no party on course to emerge a clear winner.

Opinion polls are in an effective deadlock and the country is on course for another hung parliament as polling booths open up and down the country at 7am today.

Last-ditch appeals by party leaders did little to break the opinion poll deadlock.

David Cameron said the way voters cast their ballots would "define a generation" and appealed for more time to build a better Britain, warning a Labour government would be "held to ransom" by Scottish nationalists.

But Ed Miliband accused him of hiding the truth about deep spending cuts that posed a "real and present danger" to families' finances and urged people to bring an end to "five years of unfairness, five years of failure".

Among the last set of polls taken ahead of the vote, three showed the main parties neck and neck, three had the Conservatives in front by a single point and one gave Labour a two-point advantage.

Prime Minister David Cameron and his wife Samantha leave after voting in Spelsbury

David Cameron said the way voters cast their ballots would "define a generation" and appealed for more time to build a better Britain, warning a Labour government would be "held to ransom" by Scottish nationalists.

But Ed Miliband accused him of hiding the truth about deep spending cuts that posed a "real and present danger" to families' finances and urged people to bring an end to "five years of unfairness, five years of failure".

In one of the biggest pre-election polls, a YouGov survey of 10,000 voters for The Sun had the main parties on 34% each - but with a significant 17% saying they were yet to make up their minds - a figure put as high as 25% in a ComRes poll for ITV and the Daily Mail.

In the past such a tie would have been enough to propel Ed Miliband into Downing Street but an SNP surge in Scotland threatens to rob Labour of dozens of its traditional strongholds north of the border and of the chance to govern alone.

A YouGov poll in Scotland for The Times show Nicola Sturgeon's party - with which Mr Miliband has ruled out any formal deal - enjoying 48% of support to Labour's 28%, putting several key figures including Scottish Labour leader Jim Murphy in peril of losing their seats.

Ms Sturgeon said her party was "within touching distance" of winning a majority of Scottish seats at Westminster for the first time and being able to make sure "the voice of Scotland is going to be heard more loudly at Westminster than it has ever been heard before".

The SNP leader Nicola Sturgeon casts her vote in Glasgow

She has appealed to Labour to join forces to "lock out" the Conservatives but warned her MPs would vote down a future Labour budget if it failed to end "Tory austerity" - a threat that has been seized on by the Tories as a central theme of its campaign.

Nick Clegg - who faces a fight to hold on to his own Sheffield Hallam seat - urged voters to stick with the Liberal Democrats as the only party able to provide a "stable" influence to a Tory or Labour administration.

He has refused to share power with the SNP or Ukip and indicated he would not form a minority coalition that depended on the votes of Nicola Sturgeon's or Nigel Farage's party.

Several prominent Lib Dem figures - including cabinet ministers Vince Cable, Danny Alexander and Ed Davey - are seen as vulnerable to a collapse in support for the party after five years of governing in coalition with the Conservatives.

Ukip leader Nigel Farage predicted many undecideds would swing behind the Eurosceptic party as it seeks to translate regular third places in national polls into an influential Commons presence in any post-election negotiations.

"We have a feeling there are lots of people out there who are shy Ukippers who don't tell the opinion pollsters how they will vote," he told a rally - adding he was looking forward to the established parties waking up tomorrow with a "huge hangover".

The Green Party will also hope to increase its parliamentary presence, heavily targeting three seats in a push to underline the increasingly fractured political make-up of the electorate.

Rounding off a non-stop 36-hour push with a rally in Carlisle, Mr Cameron told activists: "This is the election that will define this generation.

"It comes down to a choice of leadership. Whether you want me to continue leading our country and taking it forward, or whether you want Ed Miliband to go back to the start and waste all the work of the last five years.".

Labour would have a "credibility" problem if it was not the largest party and relied on the SNP to govern, he said, and appeared to hint that he would be ready to consider another alliance with the Liberal Democrats if it was "the right thing for the country".

Mr Miliband, on stage in Leeds, called on Labour to campaign "down to the wire" as the party aimed to have another million "conversations" with voters in key marginal constituencies throughout polling day.

He said the Tories planned "the most extreme spending cuts of any political party for a generation" that posed "a clear and present danger to the family finances of working people".

"We're fighting for a Britain where everyone plays by the same rules, where we take on the tax evaders, the hedge funds and the Tory donors and say: enough is enough," he said.

"We're fighting for a Britain where we rescue our precious National Health Service and run it with the right values at its heart. And we're fighting for a Britain that's more fair, more equal, more tolerant, more prosperous and more just."

Polling stations will be open from 7am to 10pm in what will be the busiest General Election day since 1979, with nearly 10,000 council seats also up for grabs.